Mod. 459 Half Cock issues

[BigBoss3006]

Relating to my thread about modernizing the 459, i was able to get one for pretty cheap from a LGS. Its got the short XM9 trials extractor, and does not fall into the serial number range for the recall. When set to half cock, if you pull the trigger slowly, the hammer will fall onto the half-cock notch without hitting the firing pin. If you do a DA pull slowly, it will do the same. A fast DA pull or any SA pull doesnt cause the hammer to fall to the half cock notch, and strikes the firing pin as expected.

I was planning to swap the trigger, draw bar, and hammer to MIM 3rd gen parts to smooth up the pull and get rid of the half cock anyways. Should i be looking to replace the sear lever as well?

 

[JohnHL]

I would like to try to answer your questions, Boss, but there are some things that are not clear to me.

Relating to my thread about modernizing the 459, i was able to get one for pretty cheap from a LGS. Its got the short XM9 trials extractor, and does not fall into the serial number range for the recall.

The recall says the manual safety should drop the hammer to the "at-rest" position from either full cock, or when the hammer is sitting on the half cock notch.

If it does not, the recall fix is a new, properly decock timed sear release lever.

When set to half cock,

When what is set to half cock?

if you pull the trigger slowly, the hammer will fall onto the half-cock notch without hitting the firing pin. If you do a DA pull slowly, it will do the same. A fast DA pull or any SA pull doesnt cause the hammer to fall to the half cock notch, and strikes the firing pin as expected.

With the safety engaged, the trigger should be dead.

I was planning to swap the trigger, draw bar, and hammer to MIM 3rd gen parts to smooth up the pull and get rid of the half cock anyways. Should i be looking to replace the sear lever as well?

Replacing the trigger, hammer, and sear with MIM parts will definitely smooth the action and eliminate the half cock notch.

Anytime fire control parts are replaced, it's always prudent to check decock timing and replace the sear release lever as needed.

John

 

[BigBoss3006]

Thanks John, let me clarify. With the hammer pulled back onto the half cock position, the safety does not fully engage, and does not drop the hammer to the at rest position. The safety lever travels roughly 30% of the way into the safe position and stops.

When squeezing the trigger slowly with the hammer at the rest position, with the safety off, the hammer will fall from the cocked position to the half cock position. This is not something i've seen attributed to the recall. Thats what i was also wondering about

 

[JohnHL]

Thanks John, let me clarify. With the hammer pulled back onto the half cock position, the safety does not fully engage, and does not drop the hammer to the at rest position. The safety lever travels roughly 30% of the way into the safe position and stops.

That means your pistol has failed the test, and qualifies for the recall.

When the manual safety lever is moved to the "on-safe" position, the manual safety body should push down on the sear release lever, and the sear release lever should push the sear forward, out of engagement with the hammer notch, whether that be the single action notch or the half cock notch, dropping the hammer to the "at-rest" position.

When squeezing the trigger slowly with the hammer at the rest position, with the safety off, the hammer will fall from the cocked position to the half cock position. This is not something i've seen attributed to the recall. Thats what i was also wondering about

Squeezing the trigger slowly should still bring the hammer all the way back by virtue of the draw bar's hooks and the hammer's double action notches.

It sounds as though the hammer is slipping off the draw bar hooks and falling with less energy while the draw bar is not simultaneously pulling the sear far enough forward to clear the hammer's half cock notch.

While this is at least partially the result of the tentative trigger pull, it could also indicate a problem with the draw bar and it's hooks.

As you already plan to replace the trigger, hammer, and sear with MIM parts, you should probably take the extra step and replace the draw bar also. (They have been improved over the earlier design.)

John

 

[BigBoss3006]

Thanks John. That sounds like it would describe what is happening with my trigger pull.

With that said, i cant recall off the top of my head. Are 4006 trigger components compatible with 5906 and subsequently 459's?

 

[JohnHL]

Thanks John. That sounds like it would describe what is happening with my trigger pull.

With that said, i cant recall off the top of my head. Are 4006 trigger components compatible with 5906 and subsequently 459's?

Yes!

John